What is Tridentine Mass?

What is Tridentine Mass?
The Tridentine Mass is a common name for the form of the Roman Rite Mass contained in the typical editions[1] of the Roman Missal that were published from 1570 to 1962. It was the most widely celebrated Mass liturgy in the world during that time period (as the present form of the Roman Rite is today), and it was celebrated in the Latin language in nearly every country and region.
The term "Tridentine" is derived from the Latin word Tridentinus, which means "related to the city of Trent, Italy". It was in response to a decision of the Council of Trent that Pope Pius V promulgated the 1570 Roman Missal, making it mandatory throughout the Western Church, excepting those regions and religious orders whose existing missals dated from before 1370.
In 2007, Pope Benedict XVI issued a motu proprio entitled Summorum Pontificum, accompanied by a letter to the world's bishops. The Pope stated that the 1962 edition of the Roman Missal is to be considered as an "extraordinary form" (forma extraordinaria)[4] of the Roman Rite, of which the Missal as revised by Pope Paul VI in 1970 is the ordinary, normal or standard form. As a result, some refer to the 1962 Tridentine Mass as "the extraordinary form" of the Mass. It is also often referred to as the "usus antiquior" or "antiqua forma" (old use/old standard), to differentiate from the new rite in use since 1970.
The Mass is divided into two parts, the Mass of the Catechumens and the Mass of the Faithful. Catechumens, those being instructed in the faith, were once dismissed after the first half, not having yet professed the faith. Profession of faith was considered essential for participation in the Eucharistic sacrifice.
This rule of the Didache is still in effect. It is only one of the three conditions (baptism, right faith and right living) for admission to receiving Holy Communion that the Catholic Church has always applied and that were already mentioned in the early second century by Saint Justin Martyr: "And this food is called among us the Eucharist, of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined"